I want to add a 5 X 9 gable-end roof to the front of my house over the front door/porch area. The 9' length is the side I need to attach to the existing roof. The existing roof is a simple gable with the eaves at the front of the house quite low ...maybe 8' high when standing on the front porch.

I'll start by building a 5X9 frame on the ground, sheath it, then bolt it to existing roof, and support it with 2 columns on the other side. My question is how do I build and attach the new roof to the existing roof? I would greatly appreciate any advise.